不同胶结厚度下粒间胶结力学特性的试验研究

为研究胶结物厚度对粒间胶结强度的影响，在蒋明镜等1－4]已完成的0.6 mm厚度的环氧树脂和水泥微观胶结模型试验基础上，进一步选取1.0 mm和1.5 mm两种胶结厚度，通过一系列接触力学特性测试，并结合0.6 mm厚度的试验数据，分析了在不同胶结厚度和不同胶结物类型下，粒间胶结强度指标的变化规律。试验结果表明：随着胶结厚度的增加，峰值抗拉荷载增大，峰值抗压荷载减小；同一胶结厚度下，随着法向压力的增大，两种胶结物的峰值抗剪和抗扭荷载均先增大后减小，而同一法向压力下，随着胶结厚度的增加，二者的峰值抗剪和抗扭荷载均随之减小。在三维应力空间中（法向压力-扭矩-剪力），两类胶结强度包线分别为水滴状、橄榄球状且随胶结厚度的增加而缩小，但形状不发生变化。

Experimental study of mechanical behaviors of bonded granules under different bond thicknesses

In order to investigate the effect of bond thickness on the mechanical behavior of idealized bonded granules, based on the previous work in References 1-4], another two kinds of bond thicknesses (i.e. 1.0 and 1.5 mm) between granules are investigated. Then, a series of mechanical tests are performed on the idealized bonded granules with two different bond thicknesses i.e. 1.0 and 1.5 mm, and two different bonding materials, i.e. epoxy resin and Portland cement. The test results show that the effects of bond thickness on the mechanical behaviors of two kinds of bonded granules with different bonding materials are nearly the same, i.e. the peak tension force increases with the increasing of bond thickness, while the peak compression force decreases with the increasing of bond thickness. With the same bond thickness, the peak shear force and rolling resistance increase with the increase of normal force firstly, and then decrease when normal force exceeds a special value. At a given normal force, both the peak shear strength and the rolling resistance will decrease with the increasing of bond thickness. Moreover the strength envelope in the normal-torsion-shear space shrinks almost analogously when the bond thickness changes from 0.6 to 1.5 mm.